1. Field of the Invention
This invention relates generally to telecommunications. More particularly, it relates to distributed Emergency Call Systems.
2. Background of Related Art
A 911 emergency call system bridges local government entities and call service providers, to route 911 voice calls to proper emergency dispatch personnel.
In particular, the 911 emergency call system routes a 911 voice call to a Public Safety Answering Point (PSAP) (i.e. a 911 dispatcher/emergency call center) to administer proper emergency services. The 911 emergency call system preferably routes a 911 voice call to a Public Safety Answering Point (PSAP) within closest geographic proximity to an originating communication device.
FIG. 5 demonstrates a conventional 911 call system call flow.
In particular, a 911 voice call is placed via an originating communication device (e.g. a landline communication device, a wireless communication device, etc.), as depicted in step 500. In step 510, a call service provider servicing the originating communication device detects that a 911 voice call has been placed. If the originating communication device is not able to be serviced by an affiliated call service provider (e.g. the communication device is outside the service jurisdiction of an affiliated call service provider, the communication device is not subscribed to any service(s) provided by a call service provider, etc.), 911 call processing is defaulted to a call service provider servicing a geographic location established for the originating communication device. In step 520, an applicable call service provider routes the detected 911 voice call to an appropriate Public Safety Answering Point (PSAP) via conventional call routing procedures. In step 530, the detected 911 voice call is received on an appropriate Public Safety Answering Point (PSAP), and emergency service personnel are thereby dispatched accordingly.
Enhanced 911 (E911) is a reformed version of the 911 emergency call system, employed in response to advancements achieved in current communication technologies. In particular, Enhanced 911 (E911) provides accurate 911 call routing services to a wide array of previously unsupported communication devices (e.g. wireless devices, VoIP devices, etc.) In operation, Enhanced 911 retrieves E911 voice information and relevant emergency call data (e.g. a subscriber number and a geographic location) pertaining to each E911 voice call that is detected. Relevant call data is subsequently routed to an appropriate Public Safety Answering Point (PSAP).
Wireless Enhanced 911 is a particular denomination of Enhanced 911, responsible for routing 911 voice calls originated on a wireless communication device. Wireless Enhanced 911 identifies a Mobile Subscriber Identification Number (MSIN) and a current geographic location for each device that is party to a Wireless E911 voice call. Accordingly, an associated MSIN/geographic location combination is routed to an appropriate Public Safety Answering Point (PSAP) with each Wireless E911 call that is detected.
A Mobile Subscriber Identification Number (MSIN) identifying an originating 911 calling device is retrieved for Wireless E911 call processing via an Automatic Number Identification (ANI) Service.
In particular, a unique Mobile Subscriber Identification Number (MSIN) is assigned to each communication device that is subscribed to service(s) administered by a wireless/call service provider. Furthermore, each instantiation of a Mobile Subscriber Identification Number (MSIN) to a particular communication device is recorded in a database maintained by the Automatic Number Identification (ANI) service.
FIG. 6 conveys a conventional use of an Automatic Number Identification (ANI) service within a Wireless E911 call system call flow.
In particular, a Wireless E911 call is detected upon the 911 emergency call system, as depicted in step 600. Upon detection, the Automatic Number Identification (ANI) service retrieves a Mobile Subscriber Identification Number (MSIN) stored for an originating communication device, as depicted in step 610. Once retrieved, the Automatic Number Identification (ANI) service transmits the Mobile Subscriber Identification Number (MSIN) to a wireless service provider administering E911 call routing, as shown in step 620. The Mobile Subscriber Identification Number (MSIN) is subsequently received on an appropriate wireless service provider and forwarded to a Public Safety Answering Point (PSAP), as conveyed in step 630. The Mobile Subscriber Identification Number (MSIN) is thereafter received on a Public Safety Answering Point (PSAP) and emergency service personnel are thereby dispatched accordingly, as depicted in step 640.
A geographic location may be determined for an originating communication device via an active location service (e.g. GPS) residing on the calling handset. Moreover, a geographic location for an originating communication device may alternatively be determined based upon the location of a base station servicing a corresponding E911 call. A location for an originating communication device is conventionally used to route an E911 call to an appropriate Public Safety Answering Point (i.e. a Public Safety Answering Point (PSAP) within closest geographic proximity to an originating communication device). Furthermore, a geographic location for an originating communication device promotes efficient dispersal of emergency services when routed to a Public Safety Answering Point (PSAP) administering E911 call dispatching.
According to a Federal Communications Commission (FCC) mandate, all wireless devices must be permitted access to 911 emergency call services, regardless of current service subscription. Thus, the 911 emergency call system must be capable of detecting and routing 911 voice calls placed via wireless devices that are disconnected from service.
A geographic location for a disconnected wireless device may be determined for E911 call processing via conventional handset-based/network-based device location techniques. Yet, a source of an E911 voice call originated on a disconnected wireless device is not easily identifiable. In particular, a wireless device that is disconnected from service is not attributed a Mobile Subscriber Identification Number (MSIN) corresponding to a particular subscriber account. Therefore, identification of a 911 calling party may not be automatically obtained via the Automatic Number Identification (ANI) service. Moreover, it is not possible to accurately ascertain the ownership of a disconnected wireless device. Hence, 911 calls that are placed via a disconnected wireless device are fundamentally anonymous.
To reduce anonymity, wireless service providers often designate arbitrary number identifiers (e.g. MSIN, IMSI, etc.) to wireless devices that are not subscribed to service. An arbitrary number identifier is routed to a Public Safety Answering Point (PSAP) for each E911 voice call that is originated on a corresponding wireless device.
Unfortunately, the 911 emergency call system is currently afflicted with prank 911 calls originating on wireless devices that are disconnected from service.
Presently, the only information that is obtainable for an E911 voice call placed via a disconnected wireless device, is a geographic location and an arbitrary number identifier. Although a means of filtering prank 911 calls would be useful, prank 911 calls placed via disconnected wireless devices may not be filtered based solely upon an arbitrary number identifier (e.g. MSIN, IMSI, etc.) assigned to an originating communication device. First, a number identifier assigned to a disconnected wireless device is not guaranteed to be unique. Furthermore, a disconnected wireless device may change hands at any given time, e.g., a device may be sold, borrowed, traded, etc. Therefore, it is possible, e.g., that a non-prank caller may purchase a disconnected wireless device with a number identifier depicting a device used to generate prank 911 calls. In this case, if a prank 911 call placed via a disconnected wireless device is filtered according to a device's arbitrary number identifier, it is likely that a non-prank caller may be denied access to E911 emergency call services.
Due to a lack of source information, it is difficult to prevent the routing of prank 911 calls originating on wireless devices that are disconnected from service. Hence, there is a need for a solution that may accurately identify prank 911 calling devices, regardless of current service subscription, and filter the routing of 911 calls that are placed thereon.